cycle, which is also ...
cycle, which is also referred Krebs cycle or tricarboxylic cycle, is a sequence
of chemical reactions that are employed by aerobic creatures to produce stored
energy, via the process of oxidation of acetyl- CoA into adenosine triphosphate
(ATP) and carbon dioxide. The acetyl- Co A comes from fats, proteins and
carbohydrates. Numerous citric acid cycle’s components and reactions were
launched in the 1930s by a researcher known as Szent- Gyorgyi Albert. In 1937,
Albert was rewarded the Nobel Prize in Medicine for discovering fumaric acid,
which is the main element of the cycle. The Krebs cycle itself was discovered by
William Arthur Johnson and Hans Adolf Krebs in 1937. Hans Adolf Krebs was
awarded the Nobel Prize for Medicine or Physiology in 1953 (Ward, n,d ) Thus,
the report will comprehensively talk about the functioning of the citric acid
cycle. In this case, it will cover the steps of the cycle, processes and
reactions. The report will also thoroughly explain the importance of the cycle.
For instance, it acts as the central pathway of cellular respiration. Besides,
the application of the cycle will also be incorporated in the discussion.
Importance of the topic
is essential because it enables readers understand that the citric acid cycle
has two other different names, i.e., Krebs cycle and tricarboxylic acid cycle.
More so, enables readers clearly understand that the cycle is the fundamental
cellular respiration driver. In this case, it acts as a common path for the
oxidation of lipids, proteins and carbohydrates. The acetyl CoA, which emanate
from the metabolism of fatty acids, glucose and amino acids, undergoes a series
of reaction to generate energy. The CoA obtains a large amount of its energy in
the form of FADH2, NADH and ATP molecules. The NADH and the FADH2 which act as
the electron carriers will move their electrons into the chain of electron
transport. Through the oxidation of phosphoryl, the electrons will produce ATP,
essential for production of cellular energy. For instance, the ATP molecule
will generate energy essential for muscle contraction (Chabra, 2017).
not only acts as a pathway for oxidation of carbon units, it also acts as a
major path for inter-conversion of metabolites that come from deamination and
transamination of amino acids. It also provides the substrates for
gluconeogenesis, and biosynthesis for haem and nucleotide. The citric acid
cycle is Amphibolic because it plays a vital role in both synthetic and
oxidative processes. Besides, the cycle acts as the entry for nutrients. In
this case, the nutrients can enter as intermediaries of the cycle or as Acetyl
CoA. Carbohydrates get in as acetyl Co A. The fatty acids enters as Succinyl Co
A or as acetyl Co A. The amino acids penetrates at various points on the citric
acid cycle for complete synthesis or oxidation of biological compounds
depending on the needs of the cell (Chabra, 2017).
How the citric acid cycle functions
citric acid cycle, which is also known as the tricarboxylic acid cycle or Krebs
cycle, is a sequence of chemical reactions within a cell, whereby the food
molecules are broken down into water, carbon dioxide and energy. Besides, the cycle
produces NADH and FADH2, which are utilized in the transportation of electrons.
Most metabolic processes utilize the cycle’s
intermediaries in their pathways. In
eukaryotic cells, the cycle takes place within the matrix of the
mitochondria. The citric acid cycle
entails a chain of eight reactions, and utilizes a tiny molecule known as
oxaloacetate, which acts as a catalyst. The reactions of the cycle can be divided
into two varying stages. In the first phase, two carbons emanating from citrate
react with oxygen to produce CO2. The end result is a four carbon compound
known as succinyl- CoA. In the second phase, Succinyl- CoA is converted into
oxaloacetate, and therefore, increasing the possibility of restarting the
process. In every tricarboxylic cycle, two carbons are obtained from acetyl-
CoA, and two carbons react with oxygen to generate carbon dioxide (Goodsell,
Application of the topic
cycle is critical to life because of its amphibolic role. There is no citric
acid cycle enzyme absence that has been reported. Citric acid cycle can be
incorporated in the cardio- protection. For several decades, prior to the
complete explanation of the citric acid cycle, hypoxia and ischemia were
believed to stimulate the degradation of glutamate and myocardial aspartate,
which led to the creation of succinate in secluded hearts. Thus, it has been
suggested that the above- stated channeling can help in the production of ATP
when there is deficiency of oxygen. Such examinations made researchers hope
that the manipulation of the cycle can promote cardio- protection. More so,
maintaining the generation of adequate cellular energy is essential for body
functioning, and its disruption can lead to medical conditions (Czibik,
Steeples, Yavari & Ashrafian, 2014).
organisms utilize the citric acid cycle to generate energy. The acetyl- CoA which is obtained from
carbohydrates, proteins and fats is oxidized to generate ATP and carbon
dioxide. The cycle was established in 1937 by Krebs Hans Adolf and William
Arthur Johnson. The cycle is essential because it produces energy essential for
body functioning and acts as a major pathway for the metabolism of proteins,
carbohydrates and fat. The citric acid cycle acts as the powerhouse of energy.
In this regard, it offers electrons, the fuel required in the process of
oxidizing phosphoryl so as to generate ATP and energy. All these processes take
place in the mitochondria.
Chabra, N. (2017). Significance of TCA cycle. Retrieved from
Czibik, G., Steeples, V., Yavari, A., & Ashrafian , H. (2014, October 21). Citric acid
intermediates in cardio- protection. Retrieved from
Ward, C. (n.d.) The Tricarboxylic acid cycle. Diapedia. Retrieved from